Question: What is the least common multiple of 18 and 20? Another way to say this is: $\lcm(18, 20) = {?}$
Solution: The least common multiple is the smallest number that is a multiple of 18 and 20. We know that 18 x 20 (or 360) is a common multiple, but is it the least common multiple? Write out the multiples of 20 until we find a number divisible by 18. 20, 40, 60, 80, 100, 120, 140, 160, 180, So, 180 is the least common multiple of 18 and 20.